There are three hooks:
- 'pre-commit' is given an opportunity to inspect what is
being committed, before we invoke the EDITOR for the
commit message;
- 'commit-msg' is invoked on the commit log message after
the user prepares it;
- 'post-commit' is run after a successful commit is made.
The first two can interfere to stop the commit. The last one is
for after-the-fact notification.
The earlier built-in commit checker is now moved to pre-commit.
Signed-off-by: Junio C Hamano <junkio@cox.net>
